Encased microphones



May 31, 1955 E. w. BREISCHI ETAL ENCASED MICROPHONES 2 Sheets-Sheet Filed Nov. 12, 1955 mm A. Mm! 4. $2 mu E. w. BREISCH EIAL 2,709,723-

ENCASED MICROPHONES May 31, 1955 2 Sheets-Sheet 2 Filed Nov. 12, 1953 hs'ulatiozz. v

INVENTORS Edgw'W Bnez'sch and ENCASED MICROPHONES Edgar W. Brcisch, Edgewood, and John I. Seitz, Wilkinsburg, Pa., assignors to Westinghouse Air Brake Company, Wilmer-ding, Pa., a corporation of Pennsylvania Application November 12, 1953, Serial No. 391,485

6 Claims. (Cl. 179-179) The present invention relates to a microphone, and particularly to a hand-type microphone which is fully protected against moisture, dirt and other deleterious material.

In mine communication systems many difliculties are present both from a communication standpoint and from an equipment standpoint. In most mines, moisture is an ever present factor in the deterioration of the equipment used. Dirt and dust also have their deleterious effects on equipment used in the mines. With presentday methods of mining, a good deal of mine machinery is used, and the oil and grease attendant to the use of such machinery contribute to the deterioration of certain of the electrical equipment. In the particular case of a communication system, grease and dirt on the miners hands while using the microphones of such equipment have contributed to the deterioration of the microphones and their various parts. It has also been found that the microphones are damaged by rough or careless handling.

It is therefore an object of our present invention to provide a compact and rugged microphone and switch assembly which shall consist of relatively few and simple parts.

Another object of our invention is to provide a microphone and switch assembly which is fully protected by a single-piece flexible housing made of a suitable material such as rubber, neoprene, or other suitable plastic, the housing protecting the parts from shock due to rough or careless handling.

A further object of our invention is to provide an encased microphone and switch assembly wherein the microphone switch may be positively actuated through the flexible housing provided for the assembly.

In carrying out the objects of our invention, a granular carbon microphone unit is supported on a base made of insulating material, the base being provided with a suitable recess for receiving the contact making portions of the microphone button. Within the recess of the supporting base are two spring fingers for engaging the contact making portions of the microphone. The supporting base is further provided with a deep notch or slot cut into its opposite face, the contact fingers being supported within this slot and extending through to the other side or" the base through suitable recesses. The slot is so proportioned that a small microswitch may be secured within the slot for connecting the microphone into the communication circuit. The supporting base for the microphone button assembly is further provided with two small parallel slots which register with the large slot cut into the base. A spring biased U-shaped member is received within the two small parallel slots, one of the arms of the U-shaped member being adapted to engage the button of the microswitch when said memher is depressed.

The microphone and its supporting base are inserted in a metallic case, the base being sealed by a perforated mouthpiece, preferably made of a rust resistant material. As will more fully appear, the arms of the spring nited States Patent biased U-shaped actuating member for the microswitch pass through suitable openings in the metallic case. The cased microphone is provided with a one-piece flexible housing which encloses the described assembly with the exception of the perforated mouthpiece. The one-piece housing is preferablymade of rubber or a rubber compound such neoprene, the housing having molded therein a backing plate to which a U-shaped hanger is secured, the hanger permitting the suspension of the microphone from a suitable support when not in use. The molded housing is secured to the supporting base of the microphone button by means of two screws. The microphone and its switch are thus encased in a protective flexible housing, a bulge molded into the housing covering the extended U-shaped actuating member for the microswitch.

Other objects and characteristic features of our invention will appear as the specification progresses.

We shali describe one form of a microphone embodying our invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings wherein the same reference characters designate corresponding parts throughout the several views,

Pig. 1 is a front elevational view of an encased hand microphone embodying our invention.

Fig. 2 is a sectional view taken approximately along the line IIII of Fig. 1.

Fig. 3 is a sectional view taken approximately along the line IIIiIl of Fig. 2, while Fig. 4 is an elevational view of the microphone supporting base.

Referring now in detail to the drawings, the reference numeral 1 designates an encased microphone embodying our invention. The microphone 1 comprises a supporting base 2 of insulating material. One face of the supporting base 2 is formed with an annular recess 2a (Fig. 4) while the opposite face of the supporting base is provided with a large notch or slot 2b (Fig. 3). The annular recess 2a and slot 2b in the supporting base 2 are separated by a partition 2c (Fig. 2), the partition being formed with three elongated through openings 2d. The dividing partition 20 of the base is elongated to provide an extending portion 2e which forms a support for securing two spring contact fingers 3a and 3b. For purposes hereinafter appearing the contact fingers 3a and 3b are stressed to extend through the elongated openings 2d in the dividing partition of the supporting base and extend into the annular recess 2a (Fig. 2). The contact fiinger 3a has secured thereto an L-shaped member 4 of conducting material, the upstanding end of the member 4 being con nected to a terminal of a microswitch 5 secured within the slot 2b of the supporting base 2. A second L-shaped member 5 is also secured to the extending member 2e of the base dividing partition 20 and to a terminal of the microswitch 5.

The supporting base 2 is further provided with two parallel slots 2 terminating in the slot 2b. The microswitch 5 is so positioned within the slot 2b of the supporting base that the actuating button 5a thereof lies within one of the parallel slots 2;. Slidably received within the parallel slots 2 is a U-shaped member 7, a leg 7a of the U-shaped member being adapted to engage the microswitch button 5a. A coil compression spring 8 is interposed between the U-shaped member 7 and the supporting base 2, the spring being. retained within recesses 2g and 7b provided in the base 2 and the U-shaped member 7, respectively.

A carbon microphone assembly 9 is disposed on the supporting base 2 so that the contact making elements 9a and 9b on the microphone assembly are received within the annular recess 2:: of the supporting base. The cona tact fingers 3a and 31) secured to the supporting base are disposed to engage the contact making elements 9a and 9b, respectively, of the microphone assembly. The supporting baseand microphone are set into a metal casing 10, the open end of the casing-being closed by a perforated mouthpiece 11 which is preferably made of a rust resistant material. The mouthpiece 11, in addition to providing a cover for the casing 10, also holds the microphone in place against the slight bias of the spring contact fingers 3a and 3b engaging the contact making elements of the microphone assembly. The casing 10 is formed with three spaced openings 10a for receiving the legs of the U-shaped actuating member 7 and coil spring 8, the member 7 and spring 8 being assembled after the base 2 is inserted into the casing. The casing 10 is further provided with an opening 10b to accommodate the extending portion 2e of the base to which the contacts 3a and 3b and L-shaped member 6 are secured.

The microphone assembly thus far described is encased in a one-piece molded housing 12 made of a suitable insulating material which is preferably flexible. The housing material may be made of rubber, a rubber compound or a suitable plastic, but is preferably made of neoprene. The housing 12 comprises an elongated body portion 12a terminating at its lower end in a cylindrical portion 12b which is adapted to receive a protected cable 13 for connecting the microphone and switch to the communication system. The elongated body portion 12a is formed at its front face with a circular opening 120 through. which the microphone assembly described is inserted after securing the leads 14 of the cable to the spring contact fingers and microswitch. It will be noted that the body portion of the housing 12 is molded to conform to the configurations of the metal casing 10 and the perforated mouthpiece 11. The body portion 12a of the microphone housing is provided with a slight bulge 12d .to accommodate the extending portion of the U-shaped member 7. The housing bulge 12a is preferably serrated so that the thumb of the user of the microphone will not slip oif the microphone switch actuator.

Molded into the body portion of the microphone housing 12 is a plate 15 to which is secured in a suitable manner an inverted. U-shaped hanger 16 for suspending the microphone from a suitable support when not in use, the hanger 16 being molded within the material used in making the housing 12. The plate 15 and the housing 12 form a secure and permanent combination which will not separate under conditions less than rupture of the plate or the housing. The housing 12 is secured to the microphone assembly described by means of two screws 17 which pass through suitable openings in the back of the microphone housing and the fiat plate molded therein, thescrews being threaded into suitable threaded metallic eyelets 18 molded in the supporting base 2.

We have thus provided a rugged microphone assembly consisting of few and simple parts which are readily assembled. The microphone provided by our invention is further characterized by the molded resilient housing provided for the microphone and switch assembly, the housing protecting the microphone elements from the deleterious effects of-moisture, dirt and oil, and serving to protect the encased elements from shock due to careless or rough handling.

Although we have herein shown and described only one form of a microphone embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

1. An encased microphone assembly comprising, a microphone having contact making elements thereon, a base of insulating material for the microphone, the base being provided .with at least two openings,at least two contact fingers secured to one side ofthe-base and passing through the openings to engage the contact making elements of the microphone adjacent the other side of the base, a switch assembly secured to the one side of the base for connecting the microphone and contact fingers into an electrical circuit, said switch assembly including an actuating button, a spring biased member adapted to engage the actuating button of the. switch assembly upon depression of the member, a casing for said base, microphone and switch assembly; a mouthpiece secured to said casing and holding said microphone with some pressure against the contact fingers, a one-piecehousing of insulating material having ahollow body portion enclosing the base, microphoneand switch assembly; said body portion being formed with an opening for the insertion of the assembly into the housing-and to accommodate the mouthpiece, and a portion to accommodate and permit actuation of the switch actuating member; said housing having imbedded therein a supporting plate, and means for securing the housing and supporting plate to the microphone supporting base.

2. An encased microphone assembly comprising, a microphone having contact making elements thereon, a base of insulating material for the microphone, the base being formed with a first slot and two parallel slots terminating in the first slot in the one face, the base within the first slot being provided with at least two openings; at least two contact fingers secured to the base within the first slot and passing through the openings to engage the contact making elements of the microphone adjacent the other face of the base, a switch assembly secured Within the first slot of the base for connecting the microphone and contact fingers into an electrical circuit, said switch assembly including an actuating button lying within one of the parallel slots in the base, a spring biased U shaped memher slidably received within the parallel slots, one of the legsof said member being adapted to engage the actuating button of the switch assembly upon depression of the U-shaped member, a casing for said base, microphone and switch assembly; a mouthpiece secured to said casing and holding said microphone with some pressure against the contact fingers, a one-piece housing of insulating material having a hollow body portion enclosing the base, microphone and switch assembly; said body portion being formed with an opening for the insertion of the assembly and the accommodation of the mouthpiece, and a portion to permit actuation of the U-shaped member of the switch assembly; said housing having imbedded therein a supporting plate, and means for securing the housing and supporting plate to the microphone supporting base.

3. An encased microphone assembly comprising, a microphone having contact making elements thereon, a base of insulating material for the microphone, the base being formed with an annular recess in one face for receiving the contact making elements of the microphone, a first slot and two parallel slots terminating in the first slot in the other face of the base, and a partition separating the annular recess and the first slot, the partition being provided with at least two openings interconnecting the first slot and the annular recess in the base; at least two contact fingers secured to the base partition within the first slot and passing through the openings into the annular recess to engage the contact making elements of the microphone, a switch assembly secured within the first slot of the base for connecting the microphone and contact fingers into an electrical circuit, said switch assembly including an actuating button lying within one of the parallel slots in the base, a spring biased U-shaped member slidably received within the parallel slots, one of the legs of said member being adapted to engage the actuating button of the switch assembly upon depression of the lJ-shaped member, a casing for said base, a mouthpiece secured to said casing and holding said microphone with some pressure against the contact fingers, av one-piece housing of insulating material having a hollow body portion enclosing the microphone andswitch assembly, said znoa'ms body portion being formed with an opening for the insertion of the assembly into the housing and the accomodation of the mouthpiece, and a portion to permit the actuation of the U-shaped member of the switch assembly; said housing having imbedded therein a supporting plate, and means for securing the housing and supporting plate to the microphone supporting base.

4. A microphone assembly comprising, a microphone having contact making elements thereon, a base of insulating material for the microphone button, the base being formed with at least two openings; at least two contact fingers secured to one side of the base and passing through the openings to engage the contact making elements of the microphone adjacent the other side of the base, a switch assembly secured to the one side of the base for connecting the microphone and contact fingers into an electrical circuit, said switch assembly including an actuating button, a casing for said base, microphone button and switch assembly; and a mouthpiece secured to said casing and holding said microphone button with some pressure against the contact fingers.

5. A microphone assembly comprising, a microphone having contact making elements thereon, a base of insulating material for the microphone, the base being formed with a first slot and two parallel slots terminating in the first slot in one face of the base, and with at least two openings; at least two contact fingers secured to the base within the first slot and passing through the openings to engage the contact making elements of the microphone adjacent the other face of the base, a switch assembly secured within the first slot of the base for connecting the microphone into an electrical circuit, said switch assembly including an actuating button lying within one of the parallel slots in the base, a spring biased U-shaped member slidably received within the parallel slots, one of the legs of said member being adapted to engage the actuating button of the switch assembly upon depression of the U shaped member, a casing for said base, microphone and switch assembly; and a mouthpiece secured to said casing and holding said microphone button with some pressure against the contact fingers.

6. A microphone assembly comprising, a microphone having contact making elements thereon, a base of insulating material for the microphone, the base being formed with an annular recess in one face for receiving the contact making elements of the microphone, a first slot and two parallel slots terminating in the first slot in the other face of the base, and a partition separating the annular recess and the first slot, the partition being provided with at least two openings interconnecting the first slot and the annular recess in the base; at least two contact fingers secured to the base partition within the first slot and passing through the openings into the annular recess to engage the contact making elements of the microphone, a switch assembly secured within the first slot of the base for connecting the microphone and contact fingers into an electrical circuit, said switch assembly including an actuating button lying within one of the parallel slots in the base, a spring biased U-shaped member slidably received within the parallel slots, one of the legs of said member being adapted to engage the actuating button of the switch assembly upon depression of the U-shaped member, a casing for said base, microphone and switch assembly; and a mouthpiece secured to said casing and holding said microphone button with some pressure against the contact fingers.

ReferencesCited in the file of this patent UNITED STATES PATENTS 2,039,625 Blount May 5, 1936 2,267,364 Blount Dec. 23, 1941 2,390,488 Alford et al Dec. 11, 1945 

